Took me a bit to come back to this- sorry about that. Turns out farming gets busy sometimes, ha. Preparing for fall in the market garden.

In my curiosity about how humic substances are stabilized in soils, and what happens to the humics in low CEC sandy soils (as we have on our operation), I reached out to Dr. David Laird at Iowa State University, who has spent his career studying such things. He was kind enough to answer my question, though perhaps it was not the answer I would prefer to hear. This was his perspective:

Humic substances in a low CEC soil will not be stabilized easily, and will be either leached out fairly rapidly or mineralized to Co2.

They can be stabilized and protected from mineralization by 1) adsorption to clay particles (which was my hope- adsorption to those particles to then add their own enhanced exchange capacity to improve overall CEC). 2) They can be complexed with Fe, Al, and Si and protected that way, 3) they can be sequestered inside of soil aggregates which is a combination of 1 and 2 and also the low oxygen interior environment of the aggregate.

They can also be stabilized by having a severely compromised soil microbial community. Lol.

I also asked about the different fractions and inclusion of humin and how it is extracted for commercial production, and his position was that our understanding of these fractions is because of how these things behave and labs with different acids/bases etc, and that humic substances are much more dynamic in nature and do not conform to these simple partitions we have constructed. I have heard others mention this as well, Johann Lehmann at Cornell comes to mind.

What are your observations as far as Humacarb on a sandy soil with a CEC as low as 3, and how does that info from Dr. Laird fit with your knowledge of humates, @john.kempf ?

@Stephen_Sinnott

@BrianDougherty